Heteroepitaxial growth of BaTiO3 films on Si by pulsed laser deposition

Abstract

Dielectric BaTiO3 films were heteroepitaxially grown on Si (100) substrates in cube-on-cube manner by employing a conductive TiN buffer layer. An epitaxial TiN film was grown by KrF pulsed excimer laser deposition. BaTiO3 film was grown epitaxially on the TiN film at a substrate temperature higher than 600 °C and in an oxygen pressure less than 1 mTorr. This epitaxial BaTiO3/TiN layer on Si was observed to have sharp interfaces and little interdiffusion of constituent atoms by secondary ion mass spectrometry. The surface of the BaTiO3 film had a root-mean-square roughness less than 1 nm as observed by atomic force microscopy. A TiN/BaTiO3/TiN trilayer structure was formed and the dielectric property was measured for this metal-insulator-metal type capacitor. The BaTiO3 film showed a high relative dielectric constant of 803 at the frequency of 1 MHz and a low leakage current less than 10−8 A/cm2 at 2 V.